"Unexpected token" when compiling

[CryptoKira]

I need to update a legacy site that requires me to import a library.
I'm getting the error below, using react-scripts

./node_modules/@wagmi/connectors/dist/walletConnect.js 391:138
Module parse failed: Unexpected token (391:138)
File was processed with these loaders:
 * ./node_modules/react-scripts/node_modules/babel-loader/lib/index.js
You may need an additional loader to handle the result of these loaders.
|   var _this$storage3;
| 
>   return ((_this$storage3 = this.storage) === null || _this$storage3 === void 0 ? void 0 : _this$storage3.getItem(REQUESTED_CHAINS_KEY)) ?? [];
| };

Any idea how to fix this?

[ryanmio]

The error indicates that the Babel loader can't interpret the nullish coalescing operator (??). This is often due to an outdated Babel setup.

Update react-scripts: Sometimes older versions have outdated dependencies.

npm install react-scripts@latest

Custom Babel Config: Create a .babelrc with support for newer JS features like nullish coalescing.

{
  "presets": ["@babel/preset-env", "@babel/preset-react"],
  "plugins": ["@babel/plugin-proposal-nullish-coalescing-operator"]
}

Transpile Library: As a last resort, manually transpile the offending library.

Use babel-cli to output transpiled code into a new directory.

babel ./node_modules/@wagmi/connectors/dist -d ./transpiled-library
Update import paths to point to this new directory.